This paper introduces DisplayObjects, a rapid prototyping workbench that allows functional interfaces to be projected onto real 3D physical prototypes. DisplayObjects uses a Vicon motion capture system to track the location of physical models. 3D software renditions of the 3D physical model are then texture-mapped with interactive behavior and projected back onto the physical model to allow realtime interactions with the object. We discuss the implementation of the system, as well as a selection of one and two-handed interaction techniques for DisplayObjects. We conclude with a design case that comments on some of the early design experiences with the system. Author Keywords Early Prototyping, Physical User Interfaces, Augmented Reality, Organic User Interfaces. ACM Classification Keywords H5.m. Information interfaces and presentation (e.g., HCI): Miscellaneous. General Terms Human Factors.